Inhibitory effect of bromelain on MAPK phosphorylation in LPS-induced RAW264.7 macrophage cells. The cells (2 × 106 cells/well) were treated with various concentrations of bromelain for 2 h and stimulated with LPS (100 ng/mL). (A): The protein levels of phospho and non-phospho forms of the MAPK signaling molecules, including ERK, JNK, and p38 were determined in cell lysates using western blot analysis; (B–G): Phosphorylation band densities of ERK, JNK, and p38 relative to the total form in RAW264.7 macrophage cells; PB: purified bromelain, CB: crude bromelain. The results are expressed as the mean ± SD (n = 3). #
p < 0.05 indicates a significant difference from the LPS-untreated cells, ** p < 0.005 and *** p < 0.001 indicate significant differences from the LPS alone.